Trinidad is the kind of place where it's best to just wander and get lost. There aren't a lot of specific attractions or places to check off a list- it's more about the culuture, the architecutre, the music, and the friendly (and talkative!) people.
The city is fairly small and walkable (provided you can tolerate the heat!). We wandered around the heart of city and the Plaza Mayor, where you'll find lots of street markets and shops, but as you roam a bit futher, the streets become less congested and it feels more like real life. We had the best conversations and saw the most hidden gems just outside the center. In particular, the area around Tres Cruces was quite beautiful and nearly tourist-free.
Trinidad is surrounded by beautiful mountains and beaches as well. On a particularily hot afternoon, we decided to venture out of the city and visit one of the area waterfalls. We had plenty of offers for tours by horse, but at the suggestion of a friendly local at a resturant, we decided to go a bit further, by car, to Vegas Grande. He told us it was his favorite spot in all of Cuba, and after seeing pictures (on his flip phone!) of him and his friends frolicking in a picturesque swimming hole, we were sold.
The famous falls are inside the Parque Natural Topes de Collantes, and getting there is an advenuture. With a hired driver, we meandered up what seemed like endless switchbacks. Eventually, the road turned to gravel and the potholes became worse and worse. At one point the road became completely impassible, so we decided to walk an indeterminiate distance to the trailhead. Luckily it wasn't too far and we came to a makeshift "entrance" where we had to pay 9 CUCs to visit the falls. We were told it was an easy 500 meters to the falls. However, everyone failed to mention that it was a straight vertical drop switchbacking downward! It was damp and treacherous, and my friend's shoe broke halfway down, but eventually we made it. Of course, it was totally worth it! The falls were stunning and we had them all to ourselves! We took turns briefly swimming in the ice-cold mountain water, before making the trek back up, which was actually easiser than going down.